0:00:02 > 0:00:05Some say it will end in fire.
0:00:06 > 0:00:08Others think there will be a flood.
0:00:12 > 0:00:16Some tell of a great plague that will strike down humanity.
0:00:16 > 0:00:19Destruction shall come upon this evil generation.
0:00:19 > 0:00:24But all point to one thing - the world is going to end.
0:00:26 > 0:00:32Armageddon is one of humanity's most powerful and enduring ideas.
0:00:33 > 0:00:37Stories of the apocalypse stretch right back
0:00:37 > 0:00:41to the dawn of civilization, and they still make blockbuster hits today.
0:00:54 > 0:00:58It seems there is nothing we love more than a vision of the apocalypse,
0:00:58 > 0:01:01imagining how our world might end
0:01:01 > 0:01:04seems a fundamental part of being human, but where
0:01:04 > 0:01:09we once might have looked to religion for answers, many now turn to science
0:01:09 > 0:01:15both to predict what might happen and to protect us from impending doom.
0:01:18 > 0:01:20For nearly 50 years the BBC's Horizon
0:01:20 > 0:01:23has been at the forefront of science journalism.
0:01:24 > 0:01:29Charting the breakthroughs and discoveries that would change our world.
0:01:32 > 0:01:36Science and technology have enabled us to predict earthquakes,
0:01:37 > 0:01:43defeat disease, and defend ourselves from the awesome power of nature.
0:01:45 > 0:01:50Our understanding of the world around us is better now than ever before.
0:01:52 > 0:01:56But are we any closer to knowing how it's all going to end?
0:01:57 > 0:02:00And when Armageddon arrives,
0:02:01 > 0:02:03will science be able to save us?
0:02:25 > 0:02:32For thousands of years people thought the only force powerful enough to end the world was God.
0:02:34 > 0:02:37But then in 1945, all that changed.
0:02:53 > 0:02:55The horror of two world wars
0:02:55 > 0:02:59and the phenomenal power of the Hiroshima and Nagasaki bombs
0:02:59 > 0:03:03left little doubt that we were capable of annihilating ourselves.
0:03:03 > 0:03:08The creation of atomic energy had been a scientific triumph.
0:03:10 > 0:03:14But the sheer scale of death and devastation it had caused
0:03:14 > 0:03:18left the scientific community in turmoil.
0:03:27 > 0:03:30One of the earliest Horizon programmes
0:03:30 > 0:03:35reported on the moral torment that many scientists now faced.
0:03:35 > 0:03:37This week, Horizon looks at a dilemma,
0:03:37 > 0:03:41the dilemma of the scientist who, try as he might,
0:03:41 > 0:03:43cannot reconcile with his conscience
0:03:43 > 0:03:48the fear that his discoveries may eventually be used to the detriment of mankind.
0:03:48 > 0:03:50CHEERING
0:03:51 > 0:03:56Victory over Japan brings a wild ecstasy to the ordinary men and women of the triumphant nations.
0:04:00 > 0:04:03At Los Alamos, the place where the winning weapon was created,
0:04:03 > 0:04:08most join in the general mood of celebration and relief, but not all the scientists
0:04:08 > 0:04:11present at the victory parties there share the popular excitement.
0:04:11 > 0:04:15There are some among them for whom the sweets of triumph are soured by
0:04:15 > 0:04:19a frightful awareness of the evil forces their genius and efforts have released.
0:04:24 > 0:04:26We knew the world would not be the same.
0:04:28 > 0:04:34I remembered the line from the Hindu scripture the Bhagavad-Gita
0:04:36 > 0:04:40"Now I am become death, the destroyer of worlds."
0:04:43 > 0:04:46I suppose we all thought that, one way or another.
0:04:48 > 0:04:53But there was no going back. The nuclear arms race had begun.
0:04:55 > 0:04:57During the '50s and '60s,
0:04:57 > 0:05:02the super powers built increasingly bigger bombs in a bid to defend themselves from each other.
0:05:04 > 0:05:11The result was an arsenal of weapons that could wipe humanity off the face of the Earth.
0:05:21 > 0:05:24The threat of Armageddon was real
0:05:26 > 0:05:30and many people lived each day in fear of nuclear annihilation.
0:05:34 > 0:05:37When I was a kid growing up in the 1970's and early '80s
0:05:37 > 0:05:41I certainly remember information like this government handbook
0:05:41 > 0:05:43about what to do in the event of a nuclear attack
0:05:43 > 0:05:47and it's got hints like how to build a bunker in your sitting room,
0:05:47 > 0:05:49how to protect your drinking water from fallout
0:05:49 > 0:05:52and it's scary stuff because at the time
0:05:52 > 0:05:56I remember thinking that Armageddon was just a button push away.
0:06:04 > 0:06:07And the terrible responsibility of having to push that button
0:06:07 > 0:06:10rested on the shoulders of just a handful of men.
0:06:13 > 0:06:20In 1971, Horizon gained unprecedented access to their extraordinary daily lives.
0:06:25 > 0:06:27Cherie, would you bring me a cup of coffee, please?
0:06:29 > 0:06:31'Bryce Martenson is a missile commander
0:06:31 > 0:06:33'with strategic air command.'
0:06:33 > 0:06:37Chris, do you know we're going up to Grandma Jean's for Thanksgiving?
0:06:37 > 0:06:40'Every four days he leaves his family to go to an underground
0:06:40 > 0:06:44'bomb-proof command post to take charge of ten Minuteman missiles.'
0:06:48 > 0:06:52'If necessary, he is fully prepared to take part in the destruction
0:06:52 > 0:06:56'of whole nations and ultimately his family and himself.'
0:07:02 > 0:07:05Once in the heavily guarded compound,
0:07:05 > 0:07:10Martenson and his deputy are there for 36 hours of duty.
0:07:10 > 0:07:14Both have been checked on by military intelligence and psychiatrists.
0:07:14 > 0:07:16- Attention!- Carry on.
0:07:22 > 0:07:27Both are armed. If one of them suffers a psychiatric breakdown,
0:07:27 > 0:07:29it's the duty of the other to shoot him.
0:07:36 > 0:07:3860 feet under the ground, Martenson and his deputy
0:07:38 > 0:07:41have to pass through a seven ton steel door
0:07:41 > 0:07:45before reaching the entrance to the command capsule itself.
0:07:45 > 0:07:49They're now surrounded by thousands of tons of steel and concrete.
0:07:49 > 0:07:53Protected from almost anything but a direct nuclear hit.
0:07:59 > 0:08:03The red strong box contains the secret orders to be used in case of war.
0:08:03 > 0:08:06In the box are two keys.
0:08:06 > 0:08:09To fire the missiles, these have to be turned simultaneously
0:08:09 > 0:08:11in locks thirty feet apart.
0:08:14 > 0:08:17They have been trained to the highest peak of efficiency to carry out
0:08:17 > 0:08:21a task which we hope they'll never be asked to perform.
0:08:24 > 0:08:28A first strike by the total Russian missile forces would leave
0:08:28 > 0:08:32almost all of the American Minuteman missiles undamaged.
0:08:32 > 0:08:35If only half of them were used in retaliation,
0:08:35 > 0:08:40they could destroy 80% of Russian industry and 100 million people.
0:08:43 > 0:08:46They hum menacingly. If you touch them, they feel alive.
0:08:53 > 0:08:57# Don't you understand what I'm trying to say
0:08:57 > 0:09:01# Can't you feel the fears I'm feeling today
0:09:01 > 0:09:04# If the button is pushed There's no running away... #
0:09:04 > 0:09:09Thousands took to the streets in protest against the apparent insanity of the arms race.
0:09:09 > 0:09:13We will campaign until
0:09:13 > 0:09:17all the nuclear bases are cleansed from our soil!
0:09:17 > 0:09:19APPLAUSE
0:09:19 > 0:09:24The use of destruction leads to destruction. It solves nothing.
0:09:24 > 0:09:27Europe without the bomb can solve its problems.
0:09:29 > 0:09:31As far as the people were concerned,
0:09:31 > 0:09:35decades of scientific achievement had only brought us closer to
0:09:35 > 0:09:40Armageddon than ever before and there was little we could do to prevent it.
0:09:52 > 0:09:56Three, two, one, zero.
0:09:56 > 0:09:58We have commencement.
0:10:04 > 0:10:09But then in 1969, one event transformed public opinion.
0:10:14 > 0:10:17I'm at the foot of the ladder.
0:10:20 > 0:10:22I'm going to step off now.
0:10:24 > 0:10:27It's one small step for man,
0:10:27 > 0:10:32one giant leap for mankind.
0:10:36 > 0:10:39Around 500 million people watched Neil Armstrong
0:10:39 > 0:10:44step out of the Apollo 11 spacecraft onto the surface of the moon.
0:10:45 > 0:10:48It was a remarkable achievement.
0:10:51 > 0:10:54But seeing the Earth from space brought home
0:10:54 > 0:10:57just how vulnerable our planet really was.
0:11:00 > 0:11:04The survival of the entire human race depended on this
0:11:04 > 0:11:08tiny oasis in the vast emptiness of space.
0:11:15 > 0:11:18It would be another two decades before the fall
0:11:18 > 0:11:22of the Soviet Union would diminish the threat of nuclear war.
0:11:24 > 0:11:30But by the early 1970s, a new branch of science was already emerging,
0:11:30 > 0:11:34one based not on destruction, but on protection.
0:11:36 > 0:11:41Washington DC, early morning of April 22nd 1970, Earth Day.
0:11:41 > 0:11:44Young people, until this time characterised as inward-looking,
0:11:44 > 0:11:47drug-orientated, campus-rioting
0:11:47 > 0:11:50and disaffected from public life, had found a cause.
0:11:50 > 0:11:53America had discovered ecology.
0:11:53 > 0:11:58- Well, ecology is a balance of nature.- What do you mean by ecology?
0:11:58 > 0:12:03Well, to clean it up, not to pollute the atmosphere, the land, the water.
0:12:03 > 0:12:05It's the relationship between me
0:12:05 > 0:12:07and plants and animals and the world in general.
0:12:07 > 0:12:09People talk about it and that's what they do. They say,
0:12:09 > 0:12:12"I'm really for ecology," but nobody really does anything for it.
0:12:12 > 0:12:15- What is ecology then? - Going out and doing something!
0:12:17 > 0:12:22This enthusiasm for ecology was echoed by many scientists
0:12:22 > 0:12:26convinced that if we destroyed our environment,
0:12:26 > 0:12:29we would ultimately destroy ourselves.
0:12:30 > 0:12:35It's not enough to put bricks in your toilet to save water,
0:12:35 > 0:12:39or recycle your tin cans ritually or so on.
0:12:39 > 0:12:43The really critical thing, of course, is what you're doing
0:12:43 > 0:12:45to the life support systems of the planet because those
0:12:45 > 0:12:49are the systems which supply us with all of our food, maintain
0:12:49 > 0:12:52the quality of the atmosphere, dispose of all of our waste.
0:12:52 > 0:12:55If we get rid of them, we've bought the farm.
0:12:56 > 0:13:00CHANTING AND SINGING
0:13:00 > 0:13:03The ecology movement was based on working together
0:13:03 > 0:13:06to build a better future.
0:13:08 > 0:13:12Many scientists echoed this idea, believing that sharing ideas
0:13:12 > 0:13:16was the key to becoming the masters of our destiny.
0:13:17 > 0:13:21And it was this spirit of co-operation that gave them
0:13:21 > 0:13:27the confidence and the courage to tackle one of humanity's biggest killers.
0:13:32 > 0:13:36There are probably two diseases that have caused more fear
0:13:36 > 0:13:39in the population of the world than any other,
0:13:39 > 0:13:41and that is plague and smallpox.
0:13:44 > 0:13:47Smallpox is probably one of the most frightening,
0:13:47 > 0:13:49ugly diseases that one can imagine.
0:13:49 > 0:13:54I had seen worms in wounds, I had seen all kinds of rashes,
0:13:54 > 0:13:59and people amputated, but smallpox, it's the worst I've ever seen.
0:13:59 > 0:14:04Half of them were dying and there's nothing we could do.
0:14:06 > 0:14:10In the post-war era, the scourge of smallpox was still killing
0:14:10 > 0:14:1215 million people a year.
0:14:19 > 0:14:23So members of the World Health Organisation met to lay out
0:14:23 > 0:14:29the plans of an extraordinary global challenge - to end smallpox forever.
0:14:31 > 0:14:36I felt overawed by the task ahead, recognising we had
0:14:36 > 0:14:38so many languages to deal with
0:14:38 > 0:14:41that we had so many different countries to deal with, that we were
0:14:41 > 0:14:45dealing with countries where there was famine, where there was war.
0:14:45 > 0:14:47There were many scientists who said
0:14:47 > 0:14:50that this was just not possible to do.
0:14:53 > 0:14:56And in fact, at the time, even the Director General of WHO said
0:14:56 > 0:14:58it just can't be done.
0:14:59 > 0:15:01The task was immense.
0:15:01 > 0:15:06No disease had ever been eradicated from the world before
0:15:06 > 0:15:09and smallpox was endemic on every continent.
0:15:09 > 0:15:13The challenge was to vaccinate every one at risk,
0:15:13 > 0:15:17all one billion of them.
0:15:19 > 0:15:24Doctors, nurses and health workers joined forces across the globe.
0:15:26 > 0:15:29This was war and the troops worked around the clock.
0:15:32 > 0:15:35People were dying like flies and if I sleep,
0:15:35 > 0:15:38that means there is nobody else who is going to do the work.
0:15:46 > 0:15:48The best that I ever did was in a prison,
0:15:48 > 0:15:50I did 600 people in 20 minutes.
0:15:50 > 0:15:56The best I ever did in a day was something over 11,000.
0:15:56 > 0:15:57Oh, it was a real battle.
0:15:57 > 0:16:01Hundreds of thousands of people were working - health workers,
0:16:01 > 0:16:05volunteers, so many different people.
0:16:08 > 0:16:14But no matter how hard they tried, it was just too big a task.
0:16:14 > 0:16:17Vaccinating everyone at risk was impossible.
0:16:17 > 0:16:20The team needed a new strategy.
0:16:22 > 0:16:26And so we asked the question, what would we do if we were smallpox viruses?
0:16:26 > 0:16:30What would we do if we were bent on immortality?
0:16:30 > 0:16:33What we would do is, we would find another susceptible person to move to.
0:16:36 > 0:16:41Using that idea, we got on the radio to missionaries in the area
0:16:41 > 0:16:45to tell us where are the cases of smallpox.
0:16:46 > 0:16:52We used our vaccine precisely around those cases and then what was left,
0:16:52 > 0:16:56we used where we predicted the smallpox virus would go next.
0:16:58 > 0:17:02By finding every case of smallpox and vaccinating
0:17:02 > 0:17:06everyone in contact with them, they broke the chain of transmission.
0:17:08 > 0:17:11We had out-thought the smallpox virus.
0:17:12 > 0:17:15Having vanquished the disease in North America,
0:17:15 > 0:17:18South America, Europe and Asia,
0:17:18 > 0:17:24the team were finally on the trail of the very last strain in Somalia.
0:17:28 > 0:17:31They tracked the virus to this village.
0:17:33 > 0:17:35And then to this woman.
0:17:35 > 0:17:40They traced all her contacts and that's when they found him.
0:17:49 > 0:17:54Ali Maalin - the last person on the planet with smallpox.
0:18:05 > 0:18:08A disease that had plagued humanity for thousands of years
0:18:08 > 0:18:11was finally under our control.
0:18:14 > 0:18:17It was a fantastic achievement.
0:18:17 > 0:18:21In 1979, smallpox was officially eradicated
0:18:21 > 0:18:23as a threat to human life.
0:18:23 > 0:18:27Science had shown that it could put us one step ahead of Armageddon.
0:18:27 > 0:18:31Perhaps we could be masters of our destiny.
0:18:35 > 0:18:41But then in 1981, Horizon reported on a controversial new theory
0:18:41 > 0:18:45that suggested the fate of humanity was beyond our control.
0:18:52 > 0:18:56It had long been known that 65 million years ago, Earth had
0:18:56 > 0:19:03suffered a catastrophe that had wiped out nearly all living things,
0:19:03 > 0:19:06including the dinosaurs.
0:19:15 > 0:19:20No-one had managed to pinpoint what caused this mass extinction
0:19:20 > 0:19:26until a father/son team proposed a radical new idea.
0:19:28 > 0:19:33My son Walt brought along this little sample of rock,
0:19:33 > 0:19:38which he has put together in Lucite to keep it from crumbling.
0:19:38 > 0:19:40He said, "Dad, do you see this clay layer here,
0:19:40 > 0:19:42"it's about a half inch thick."
0:19:42 > 0:19:45He said, "That's when the dinosaurs went out," and I said,
0:19:45 > 0:19:51"Do tell me more about that," and so he said that not only the dinosaurs
0:19:51 > 0:19:56but 65 or 75% of all species alive on the Earth then
0:19:56 > 0:19:59suddenly disappeared. And I said, "Gee, Walt,
0:19:59 > 0:20:02"that's about the most exciting thing I've ever seen in my life."
0:20:02 > 0:20:05And he had to confess ignorance to some things, he said,
0:20:05 > 0:20:09"We really don't know how long it took, why it's there,"
0:20:09 > 0:20:17and so I said, "Maybe some of the tricks that I know as a physicist might help unravel that story,"
0:20:17 > 0:20:20and then we talked about it for the next couple of weeks
0:20:20 > 0:20:24and finally decided to look for iridium
0:20:24 > 0:20:27as a measure of the deposition rate.
0:20:27 > 0:20:31Iridium along with all the other elements
0:20:31 > 0:20:34was present in the cloud of dust that was to form the solar system.
0:20:34 > 0:20:38What little there is comes from the slow drizzle of the stuff
0:20:38 > 0:20:41that's still falling on the Earth at a known rate.
0:20:41 > 0:20:44Alvarez decided to measure how much iridium there was in the clay
0:20:44 > 0:20:47and so calculate how long it had taken to fall.
0:20:52 > 0:20:55The results surprised everyone.
0:20:55 > 0:20:58Iridium was found in large amounts,
0:20:58 > 0:21:01much more than a slow drizzle from space could explain.
0:21:02 > 0:21:08Now, there was no way that we knew of that we could explain
0:21:08 > 0:21:11such an increase by conventional,
0:21:11 > 0:21:16terrestrial chemistry or geo-chemistry.
0:21:16 > 0:21:20Luiz realised they had stumbled upon something important,
0:21:20 > 0:21:21but what did it mean?
0:21:21 > 0:21:23And I went through a lot of scenarios.
0:21:23 > 0:21:27Some of them were so wild I wouldn't even dare mention what they were,
0:21:27 > 0:21:32but I remember thinking at the time, each of them looked pretty good.
0:21:32 > 0:21:35One idea was that the iridium was showered on the Earth
0:21:35 > 0:21:37from a nearby exploding star, a supernova.
0:21:40 > 0:21:43The idea was that if the iridium had come from a super nova,
0:21:43 > 0:21:46it would have carried with it a rare type of plutonium
0:21:46 > 0:21:50that no longer exists in the solar system, plutonium 244.
0:21:53 > 0:21:55Nothing.
0:21:55 > 0:21:58- He went on churning out the ideas. - He would come up with them.
0:21:58 > 0:22:02These would be evaluated and discarded.
0:22:02 > 0:22:07After about a month and a half, he came up with one that none of us
0:22:07 > 0:22:11could knock down and that's the one that we're working on now.
0:22:16 > 0:22:21What they're working on now also comes from space.
0:22:21 > 0:22:23The vast majority of iridium-bearing meteorites
0:22:23 > 0:22:26started life as asteroids.
0:22:26 > 0:22:28Most of them in an orbit between Mars
0:22:28 > 0:22:31and Jupiter never come anywhere near the Earth.
0:22:31 > 0:22:33But the theory goes that a few are occasionally
0:22:33 > 0:22:38swung out of line by the enormous gravitational pull of Jupiter.
0:22:39 > 0:22:44A very few of these finish up in an orbit which crosses the Earth's.
0:22:44 > 0:22:48Alvarez' theory is that 65 million years ago, a huge asteroid,
0:22:48 > 0:22:53six miles wide, smashed into the Earth with devastating effects.
0:22:59 > 0:23:02It was this collision, he believes, that covered the Earth
0:23:02 > 0:23:06with iridium and wiped out the dinosaurs.
0:23:14 > 0:23:18Ten years later, Alvarez' theory became widely accepted
0:23:18 > 0:23:22when a 200 kilometre-wide impact crater the asteroid left behind
0:23:22 > 0:23:25was identified in the jungles of Mexico.
0:23:36 > 0:23:39When it became clear that a rock falling from the heavens
0:23:39 > 0:23:43had exterminated nearly all life on Earth,
0:23:43 > 0:23:46we realised just how vulnerable we were.
0:23:49 > 0:23:54The mass extinction of the dinosaurs was proof that Armageddon was real.
0:23:54 > 0:23:57If it had happened before, it could happen again.
0:23:57 > 0:24:00Against the awesome might of nature,
0:24:00 > 0:24:04our science and our technology seemed powerless,
0:24:04 > 0:24:06but if we couldn't prevent the devastation,
0:24:06 > 0:24:09we needed to get really good at something else,
0:24:09 > 0:24:11the science of prediction.
0:24:13 > 0:24:18Astronomers began scouring the heavens for killer asteroids
0:24:18 > 0:24:22that might be heading our way.
0:24:23 > 0:24:28And then radio telescopes captured the image everyone was dreading.
0:24:33 > 0:24:37A one kilometre-wide asteroid with our name on it.
0:24:40 > 0:24:44It's known as 1950 DA.
0:24:47 > 0:24:52An interesting question is, is 1950 DA the most dangerous rock in space?
0:24:55 > 0:24:59And at the moment, one could say it's the most dangerous
0:24:59 > 0:25:01known rock in space.
0:25:04 > 0:25:07Astronomers have tracked 1950 DA more closely than almost
0:25:07 > 0:25:12any other asteroid in the solar system,
0:25:12 > 0:25:17and all the indications are it is cosmic enemy number one,
0:25:17 > 0:25:25expected to collide with or come perilously close to the Earth in 2880.
0:25:30 > 0:25:34Its impact could kill hundreds of millions of people.
0:25:38 > 0:25:42If 1950 DA hit the Earth, the energy released would be
0:25:42 > 0:25:46roughly 100,000 megatons.
0:25:48 > 0:25:51Ten megatons is a very powerful hydrogen bomb.
0:25:53 > 0:25:57So this would not be a pleasant event for the Earth.
0:26:04 > 0:26:06It seems that in the mere blink of a cosmic eye
0:26:06 > 0:26:09we have a date with Armageddon.
0:26:11 > 0:26:15The world of science now faced an awesome task.
0:26:15 > 0:26:19What could it do to save the Earth?
0:26:27 > 0:26:30Jay Melosh was part of an elite group of scientists
0:26:30 > 0:26:34summoned by the US Government to tackle this new threat to humanity.
0:26:38 > 0:26:42The solution they confidently proposed would be
0:26:42 > 0:26:45to turn our weapons of mass destruction into weapons
0:26:45 > 0:26:47of mass salvation -
0:26:47 > 0:26:51attack an incoming asteroid with nuclear missiles.
0:26:53 > 0:26:56It would seem that a big nuclear weapon detonated
0:26:56 > 0:27:00either on the surface or drilled inside an asteroid
0:27:00 > 0:27:02would be the answer to this problem.
0:27:07 > 0:27:12We've been trained from watching movies like Star Wars that
0:27:12 > 0:27:14if we were to do that,
0:27:14 > 0:27:17the asteroid would disappear in a cloud of vapour.
0:27:26 > 0:27:28But then Melosh and his fellow scientists
0:27:28 > 0:27:32pointed to one very obvious snag.
0:27:32 > 0:27:39Those movies ignore the really gigantic scale of these objects.
0:27:39 > 0:27:43Even a nuclear weapon of the normal yield, 20 megatons,
0:27:43 > 0:27:46would not disperse it.
0:27:57 > 0:27:59Firing even our most powerful missiles,
0:27:59 > 0:28:0320 megaton warheads would be useless.
0:28:05 > 0:28:08In fact, it could just make matters worse.
0:28:11 > 0:28:14Scientists calculated that the explosion could simply
0:28:14 > 0:28:19shatter the asteroid, causing huge pieces of rock
0:28:19 > 0:28:23to rain down across continents and oceans.
0:28:23 > 0:28:27One huge killer would be turned into something every bit as deadly -
0:28:27 > 0:28:30a cluster bomb.
0:28:32 > 0:28:36Even if we could break it up into fragments, it's not clear that
0:28:36 > 0:28:41that would help things unless all of the fragments missed the Earth.
0:28:44 > 0:28:46Because if they didn't,
0:28:46 > 0:28:51gigantic fires could be ignited by those fragments hitting land.
0:28:55 > 0:28:58Large fragments that hit the sea could raise tidal waves
0:28:58 > 0:29:00up to four kilometres high.
0:29:05 > 0:29:07It would be utterly devastating.
0:29:14 > 0:29:18It seemed no existing nuclear weapon could save the Earth.
0:29:19 > 0:29:22What was needed was something much bigger, something that
0:29:22 > 0:29:28wouldn't just fragment an incoming asteroid, but completely vaporise it.
0:29:30 > 0:29:36Nothing that we have in our arsenals can release that much energy.
0:29:36 > 0:29:40Nevertheless, the nuclear weapons designers assure us that there
0:29:40 > 0:29:44is no theoretical limit to how big you can build a nuclear weapon
0:29:44 > 0:29:46and many were eager to try.
0:29:51 > 0:29:55So they set to calculating just how big a weapon they would need.
0:29:57 > 0:30:00The answer was staggering.
0:30:01 > 0:30:04The biggest bomb ever made would have to be
0:30:04 > 0:30:07placed on the biggest rocket ever made.
0:30:10 > 0:30:14And the whole contraption fired out of the Earth's atmosphere
0:30:14 > 0:30:17at 40,000 kilometres per hour.
0:30:21 > 0:30:26We're talking something on the order of a thousand megatons.
0:30:26 > 0:30:30Such weapons constitute a bigger threat to us
0:30:30 > 0:30:32than the asteroids themselves do.
0:30:34 > 0:30:39This weapon, if mishandled or misused, would itself be
0:30:39 > 0:30:43capable of causing a global catastrophe.
0:30:43 > 0:30:47The idea was dismissed as insane.
0:30:47 > 0:30:51Nuclear weapons, it seemed, were not the answer.
0:30:51 > 0:30:53Science had to find a better way.
0:31:06 > 0:31:09So Melosh put forward an extraordinary idea.
0:31:15 > 0:31:17He suggested building a device
0:31:17 > 0:31:21that would act like a giant magnifying glass.
0:31:24 > 0:31:26We imagine this is the asteroid.
0:31:26 > 0:31:29We get it lined up, focus it
0:31:29 > 0:31:33and we can start to vaporise the surface of the asteroid.
0:31:36 > 0:31:40If we focus the solar energy in a narrow spot on the surface
0:31:40 > 0:31:43we can actually vaporise rock, generate a jet,
0:31:43 > 0:31:47kind of like a little rocket motor, a solar-powered rocket motor,
0:31:47 > 0:31:50that will then gently push the asteroid away.
0:31:50 > 0:31:54His name for this device was a solar collector.
0:31:57 > 0:31:59This solar collector would focus
0:31:59 > 0:32:04an intense beam of the sun's energy onto the asteroid.
0:32:04 > 0:32:09The heat would burn away the surface of the asteroid, releasing energy
0:32:09 > 0:32:13which would gradually push the asteroid off course.
0:32:16 > 0:32:18It might sound like science fiction
0:32:18 > 0:32:22but it offered hope that science could save the Earth.
0:32:33 > 0:32:35But there was a problem.
0:32:36 > 0:32:41It would take at least ten years to build and deploy the solar collector
0:32:41 > 0:32:47and many asteroid hunters believed that we might not have that long.
0:32:47 > 0:32:51They estimated there could be up to 600 kilometre-wide asteroids
0:32:51 > 0:32:54still undiscovered near Earth.
0:32:54 > 0:32:58And any one of them could be heading straight for us.
0:33:08 > 0:33:12While astronomers trained their telescopes on the skies,
0:33:12 > 0:33:16other scientists were fine-tuning their instruments to find out
0:33:16 > 0:33:18what might be lurking here on Earth.
0:33:20 > 0:33:24And they discovered that nature was far more dangerous
0:33:24 > 0:33:26than they'd ever imagined.
0:33:27 > 0:33:32Increasingly sophisticated seismological research
0:33:32 > 0:33:34found that a single earthquake
0:33:34 > 0:33:38could trigger a chain reaction of devastating quakes
0:33:38 > 0:33:42capable of bringing entire nations to their knees.
0:33:46 > 0:33:49And in the Canary Islands
0:33:49 > 0:33:53an unstable volcano could cause a massive landslide,
0:33:53 > 0:33:58creating a huge tidal wave far higher than any normal tsunami.
0:33:58 > 0:34:02It would race across oceans, killing millions.
0:34:11 > 0:34:15And then, hidden beneath Yellowstone Park in Wyoming,
0:34:15 > 0:34:18geologists found an even bigger threat.
0:34:23 > 0:34:25A super-volcano.
0:34:30 > 0:34:35We realised that Yellowstone had been an ancient volcanic system.
0:34:35 > 0:34:38We suspected that it had been a caldera volcano
0:34:38 > 0:34:42but we didn't know where the caldera was or how large it was.
0:34:45 > 0:34:48It wasn't until photographs were taken from the air
0:34:48 > 0:34:51that the true scale of the caldera was revealed.
0:34:55 > 0:34:57It was a monster.
0:34:57 > 0:35:0170 kilometres across, 30 kilometres wide.
0:35:04 > 0:35:06Beneath it lay a vast magma chamber
0:35:06 > 0:35:09that encompassed almost the entire park.
0:35:16 > 0:35:20The question was, when would it erupt?
0:35:24 > 0:35:27To find out, geologists needed to work out
0:35:27 > 0:35:30when it had erupted in the past,
0:35:30 > 0:35:34so they examined the ancient sheets of hardened ash
0:35:34 > 0:35:39and they discovered something unexpected -
0:35:39 > 0:35:45three different layers from three different eruptions.
0:35:45 > 0:35:49Quite amazingly, we realised that there was a cycle of caldera-forming eruptions,
0:35:49 > 0:35:53these huge volcanic eruptions, about every 600,000 years.
0:35:59 > 0:36:02Yellowstone was on a 600,000-year cycle
0:36:02 > 0:36:06and the last eruption was 600,000 years ago.
0:36:08 > 0:36:14And there were worrying signs that the volcano was once again beginning to stir.
0:36:18 > 0:36:24Professor Bob Smith has been working in the park for most of his career.
0:36:27 > 0:36:32I was working at the south end of this lake in a place called Peale Island.
0:36:32 > 0:36:37I was standing on the island one day and I noticed a couple of unusual things.
0:36:37 > 0:36:42The boat dock that we would normally use at this place seemed to be under water.
0:36:43 > 0:36:47That evening, as I was looking over the expanse of the south end
0:36:47 > 0:36:51of the lake, I could see trees that were being inundated by water.
0:36:53 > 0:36:56I took a look at these trees and they were being
0:36:56 > 0:36:59inundated with water a few inches, maybe a foot deep.
0:37:01 > 0:37:03What does it mean? We did not know.
0:37:07 > 0:37:11Bob commissioned a survey to measure the elevation of the park
0:37:11 > 0:37:12above sea level.
0:37:14 > 0:37:17He compared these figures to those of a survey carried out in the 1920s.
0:37:20 > 0:37:22The results were surprising.
0:37:22 > 0:37:26They seemed to show that the ground was heaving upwards.
0:37:33 > 0:37:35The surveyor said, "There's something wrong."
0:37:35 > 0:37:39And he said, "It's not me. It's got to be something else."
0:37:39 > 0:37:41So we went through all the measurements again,
0:37:41 > 0:37:43trying to be very careful
0:37:43 > 0:37:49and the conclusion kind of hit me in the face. It said this caldera has uplifted, at that time,
0:37:49 > 0:37:53740 millimetres in the middle of the caldera.
0:37:57 > 0:38:01The ground beneath the north of Yellowstone was bulging up,
0:38:01 > 0:38:05tilting the rest of the park downwards.
0:38:05 > 0:38:07This was tipping out the south end of the lake,
0:38:07 > 0:38:11saturating the shore-side trees with water.
0:38:14 > 0:38:17The scientists realised there was only one thing that could
0:38:17 > 0:38:21make the earth rise up in this way -
0:38:21 > 0:38:23a vast, living magma chamber.
0:38:26 > 0:38:28The Yellowstone super-volcano was alive.
0:38:31 > 0:38:36And if the calculations were correct, the next eruption was already overdue.
0:38:45 > 0:38:48They predicted that when this super-volcano erupts again
0:38:48 > 0:38:53it will have a devastating impact across the whole world.
0:39:03 > 0:39:08Gigantic plumes of ash and debris will be thrown into the atmosphere,
0:39:08 > 0:39:10blotting out the sun.
0:39:24 > 0:39:29Global temperatures will plummet, devastating agriculture
0:39:29 > 0:39:32and pushing humanity to the brink of extinction.
0:39:40 > 0:39:43It seemed the more scientists scrutinised nature
0:39:43 > 0:39:47the more terrifying threats they found.
0:39:47 > 0:39:51Increasingly sophisticated scientific techniques might have
0:39:51 > 0:39:55brought us greater knowledge but we were scaring ourselves stupid.
0:39:55 > 0:39:59And as the millennium approached we were gripped by Armageddon fever.
0:39:59 > 0:40:03We even convinced ourselves that the turn of the new year itself
0:40:03 > 0:40:05would spell our doom.
0:40:05 > 0:40:08Patients' lives could be at risk because the Health Service
0:40:08 > 0:40:13may not be ready to deal with the so-called Millennium Bug.
0:40:13 > 0:40:18At the stroke of midnight, the Millennium Bug would cause computers to crash,
0:40:18 > 0:40:20power grids to seize
0:40:20 > 0:40:22and planes to fall from the skies.
0:40:24 > 0:40:26Three, two, one.
0:40:26 > 0:40:29BELL CHIMES
0:40:38 > 0:40:41When the New Year arrived uneventfully,
0:40:41 > 0:40:44hysteria turned to apocalypse fatigue.
0:40:47 > 0:40:50We'd believed all the hype and now started to wonder
0:40:50 > 0:40:53if the scientists were crying wolf.
0:40:53 > 0:40:59But then, just when we thought we were safe, an event witnessed by millions changed everything.
0:41:22 > 0:41:28Nearly 3,000 people died in the terrorist attacks of September 11th 2001.
0:41:29 > 0:41:34It was a stark reminder that there were some things we could never predict
0:41:34 > 0:41:38and that Armageddon could yet be a man-made catastrophe.
0:41:39 > 0:41:43These shocking acts of violence put the world on red alert.
0:41:50 > 0:41:54And then on Boxing Day, 2004...
0:42:00 > 0:42:02..the Indian Ocean Tsunami,
0:42:02 > 0:42:05one of the most devastating natural disasters in living memory,
0:42:05 > 0:42:11claimed over 200,000 lives in a single day.
0:42:21 > 0:42:26Dire warnings of the apocalypse can sometimes feel dramatic
0:42:26 > 0:42:27and unreal.
0:42:27 > 0:42:30But these events were a chilling reminder that our lives
0:42:30 > 0:42:33could be snuffed out in an instant.
0:42:40 > 0:42:42Science was powerless to prevent these tragedies,
0:42:42 > 0:42:44but one year later,
0:42:44 > 0:42:47when devastation looked set to strike again,
0:42:47 > 0:42:50scientists made sure they were ready.
0:42:54 > 0:42:58Good evening, European governments have been told to take urgent action
0:42:58 > 0:43:01to prepare for a possible flu pandemic.
0:43:01 > 0:43:07The virus found is H5N1 - highly pathogenic virus.
0:43:10 > 0:43:14Any bird flu could cause a pandemic.
0:43:14 > 0:43:18But hidden inside H5N1, is something that makes it a more dangerous virus
0:43:18 > 0:43:20than any we've seen before.
0:43:21 > 0:43:25This particular H5N1 virus
0:43:25 > 0:43:29falls into the category of what we call a highly pathogenic virus.
0:43:29 > 0:43:31Um, much, much more deadly
0:43:31 > 0:43:35than your run-of-the-mill avian influenza viruses.
0:43:38 > 0:43:41When we analysed it, we found a tiny extra piece
0:43:41 > 0:43:43of genetic material
0:43:43 > 0:43:46that's in one of the genes of the virus.
0:43:48 > 0:43:54The tiny genetic anomaly turns H5N1 into a particularly nasty killer.
0:43:56 > 0:44:00What is different about the H5N1 virus
0:44:00 > 0:44:01is that this very small change
0:44:01 > 0:44:04allows the virus to spread throughout the body
0:44:04 > 0:44:08infecting various organs and tissues around the respiratory tract.
0:44:08 > 0:44:12And of course, we've seen the result quite clearly,
0:44:12 > 0:44:15many of these people who have become infected with H5N1
0:44:15 > 0:44:17are dying from multi-organ failure.
0:44:29 > 0:44:33The idea that a killer bird-flu virus could
0:44:33 > 0:44:37take hold in the human population isn't scientific theory -
0:44:37 > 0:44:38it's historical fact.
0:44:38 > 0:44:41Medical archives reveal a pattern of flu pandemics
0:44:41 > 0:44:44stretching back through the centuries.
0:44:44 > 0:44:48The most devastating outbreak of all occurred in 1918,
0:44:48 > 0:44:52shortly after the end of the First World War.
0:44:52 > 0:44:56A deadly strain of avian flu spread rapidly across the globe,
0:44:56 > 0:45:00carried in the lungs of soldiers returning home to their families.
0:45:02 > 0:45:04The death toll was terrifying.
0:45:08 > 0:45:12Within 14 months, the virus had taken 15 million lives.
0:45:20 > 0:45:23'The biggest shock, I guess, about 1918 was
0:45:23 > 0:45:26'the way the virus turned its face and attacked
0:45:26 > 0:45:29'young people between the ages of 25 and 35.'
0:45:29 > 0:45:32They are not the sort of young people who were normally killed
0:45:32 > 0:45:36by an influenza virus, but in 1918 they were.
0:45:38 > 0:45:40'The virus spared the elderly -
0:45:40 > 0:45:43'they're usually the most vulnerable - and attacked the young group.
0:45:43 > 0:45:46'Whenever you think about 1918, you think,'
0:45:46 > 0:45:48"Oh, my goodness, I hope that's not going to happen again."
0:45:51 > 0:45:55The flu strain responsible for the 1918 pandemic was H1N1.
0:45:55 > 0:45:58Not the same virus that is threatening us today,
0:45:58 > 0:46:02but the similarities between the two are striking.
0:46:05 > 0:46:07'At the moment, with H1N1,
0:46:07 > 0:46:10'140 people have died, in a population of six billion.
0:46:11 > 0:46:14'People come to me and they say, "That's not many."'
0:46:14 > 0:46:17But my answer to that is, go back to the year before 1918.
0:46:17 > 0:46:21There, you had 140 people dead, 140 soldiers dead.
0:46:21 > 0:46:24'There you had a virus that didn't seem to spread at all,'
0:46:24 > 0:46:31but within a year it had exploded, and killed 50 million people.
0:46:31 > 0:46:34So, there's a warning there.
0:46:34 > 0:46:39We cannot ignore a virus that's done that in the past. We really can't.
0:46:42 > 0:46:46The predictions surrounding avian flu were truly apocalyptic.
0:46:48 > 0:46:52Virologists warned that millions could become infected and die,
0:46:52 > 0:46:55plunging society into chaos.
0:46:59 > 0:47:02But in the end, the pandemic never came.
0:47:06 > 0:47:09Scientists are keen to warn us when they spot a looming disaster,
0:47:09 > 0:47:12but when their predictions don't come true,
0:47:12 > 0:47:14they're often accused of scaremongering.
0:47:14 > 0:47:18Yet their most persistent warning, the one they've been shouting about
0:47:18 > 0:47:23for decades now, is still something that many people don't want to hear.
0:47:24 > 0:47:27It's a story Horizon has been following since the '80s.
0:47:32 > 0:47:35Our world is getting hotter.
0:47:35 > 0:47:39The atmosphere is changing, trapping more heat from the Sun.
0:47:39 > 0:47:43Changing with it may be climate, agriculture and the level of the sea.
0:47:44 > 0:47:49The cause is odourless, colourless and non-toxic, and it's man-made.
0:47:51 > 0:47:55Some of the trouble comes from this power station at Vesteros in Sweden.
0:47:55 > 0:47:59The emissions should be harmless - water vapour
0:47:59 > 0:48:04and carbon dioxide, or CO2 - but carbon dioxide is the problem.
0:48:06 > 0:48:12Burning coal, or any fossil fuel such as oil or gas, makes CO2.
0:48:12 > 0:48:16We put 18 billion tonnes of it out into the atmosphere each year.
0:48:16 > 0:48:18CO2 traps heat like a giant greenhouse,
0:48:18 > 0:48:21and it may be changing the climate of the Earth.
0:48:26 > 0:48:30'20 years ago, when this matter was discussed among scientists,
0:48:30 > 0:48:33'the response was one of dismissing it -
0:48:33 > 0:48:36'"This is fiction, we don't believe it."
0:48:36 > 0:48:41'Today, many are concerned, and that's a major difference.'
0:48:41 > 0:48:44It's been an evolutionary process in people's mind
0:48:44 > 0:48:48as well as with regard to our knowledge about the phenomenon.
0:48:48 > 0:48:52What is happening is that we as human beings are
0:48:52 > 0:48:56bringing about a climatic change.
0:48:56 > 0:48:59We are emitting things into the atmosphere now with a rate
0:48:59 > 0:49:03that will change the climate more rapidly
0:49:03 > 0:49:07than it has changed naturally during the last hundred thousands of years.
0:49:09 > 0:49:10# I've got the brains
0:49:10 > 0:49:13# You've got the looks
0:49:13 > 0:49:15# Let's make lots of money
0:49:16 > 0:49:18# You've got the brawn... #
0:49:18 > 0:49:23But the apocalyptic warnings fell on deaf ears.
0:49:27 > 0:49:32The 1980s were the boom years of optimism and progress,
0:49:32 > 0:49:34and consumerism was running wild.
0:49:38 > 0:49:41The idea that our success and progress could be harming
0:49:41 > 0:49:45the planet wasn't something that people really wanted to hear.
0:49:45 > 0:49:48After all, if global warming was making Britain
0:49:48 > 0:49:51a few degrees warmer, what was there to worry about?
0:49:56 > 0:49:57But as the years passed,
0:49:57 > 0:50:01the complexities of climate change started to unfold.
0:50:03 > 0:50:06Scientists began to think that a few degrees of warming
0:50:06 > 0:50:11in some parts of the world could trigger global chaos.
0:50:18 > 0:50:20This is the cleanest place on Earth,
0:50:20 > 0:50:23the Clean Air Facility at the South Pole,
0:50:23 > 0:50:27where the impact of human civilisation is measured -
0:50:27 > 0:50:29the Earth's environmental oracle.
0:50:31 > 0:50:32CFCs...
0:50:33 > 0:50:37It was in Antarctica that the hole in the ozone layer was first spotted.
0:50:40 > 0:50:44It is here the increase in carbon dioxide levels is measured,
0:50:44 > 0:50:48and it is here that scientists are prophesying doomsday...
0:50:48 > 0:50:49-35.5.
0:50:49 > 0:50:53..global warming at the end of the Earth.
0:50:55 > 0:50:58For it has been predicted that, if temperatures rise,
0:50:58 > 0:51:02part of the vast ice sheet that covers Antarctica
0:51:02 > 0:51:04might suddenly collapse.
0:51:06 > 0:51:07And Antarctica is warming up.
0:51:11 > 0:51:15# We're all going on a summer holiday... #
0:51:16 > 0:51:19We're heading for Leonie Island over there.
0:51:19 > 0:51:21It's a small island about four kilometres square
0:51:21 > 0:51:23with a thin ribbon of vegetation along one side of it.
0:51:33 > 0:51:37Head of terrestrial life sciences for British Antarctic Survey,
0:51:37 > 0:51:40David Walton has been measuring climate change,
0:51:40 > 0:51:43and on Leonie Island the evidence is irrefutable.
0:51:48 > 0:51:51The desert that is Antarctica is blooming.
0:51:51 > 0:51:54There's a tremendous amount of Colobanthus up here,
0:51:54 > 0:51:56growing amongst the mosses.
0:51:56 > 0:51:58It looks really good, lots of vegetation.
0:52:00 > 0:52:03Lots of grass all along here, colonising all the bare ground,
0:52:03 > 0:52:05and in the cracks up amongst the rocks.
0:52:05 > 0:52:08'We've been mapping these plants for some time.'
0:52:08 > 0:52:11Over 25 years, we've noticed a tremendous increase
0:52:11 > 0:52:14in their spread, into areas they'd previously never colonised,
0:52:14 > 0:52:18and this paralleled measurements that we were making which showed
0:52:18 > 0:52:21that the mean temperature was going up year on year.
0:52:21 > 0:52:24The records show that, in the last 50 years,
0:52:24 > 0:52:29the Antarctic Peninsula has warmed by an unprecedented 2 degrees Celsius.
0:52:36 > 0:52:40The Antarctica team feared this increase in temperature might
0:52:40 > 0:52:42cause the ice sheet to collapse.
0:52:46 > 0:52:48And if that happened,
0:52:48 > 0:52:50they predicted global sea levels could
0:52:50 > 0:52:52rise by as much as three metres,
0:52:52 > 0:52:55swamping coastal towns and cities across the world.
0:53:06 > 0:53:09And there was evidence it was already beginning to happen.
0:53:11 > 0:53:14..have discovered that an ice shelf which used to be
0:53:14 > 0:53:18the size of East Anglia has completely collapsed...
0:53:18 > 0:53:23Since that programme was made, a further 2,500 cubic kilometres
0:53:23 > 0:53:25of the polar ice sheets have melted into the sea.
0:53:30 > 0:53:35That's more fresh water than could flow over Niagara Falls in 40 years.
0:53:46 > 0:53:50But scientists realised that rising sea levels might only be
0:53:50 > 0:53:51half the problem.
0:53:51 > 0:53:55Fresh meltwater flooding into the oceans could also disrupt
0:53:55 > 0:53:58a natural cycle we all depend upon...
0:54:04 > 0:54:06..the Gulf Stream.
0:54:06 > 0:54:07Britain bathes in its heat.
0:54:09 > 0:54:12It begins south of the Equator, absorbs heat from the tropics
0:54:12 > 0:54:14and delivers it to our shores.
0:54:14 > 0:54:18It means we can swim in the sea at the same latitude
0:54:18 > 0:54:20that Canada has polar bears.
0:54:22 > 0:54:27But the most important thing about it happens further north.
0:54:27 > 0:54:28It sinks.
0:54:28 > 0:54:31This sinking is caused by the salt in the water.
0:54:32 > 0:54:37The dense salty water plunges to the bottom and is pushed back south,
0:54:37 > 0:54:40where it warms and rises, and the whole cycle begins again.
0:54:53 > 0:54:58For thousands of years, the current has circulated without interruption.
0:54:58 > 0:55:03But then a fisheries researcher working off the coast of Scotland
0:55:03 > 0:55:05discovered something alarming.
0:55:07 > 0:55:12This graph shows the salinity, or saltiness, of the bottom water.
0:55:12 > 0:55:15It's the saltiness from 1900 to the present day.
0:55:18 > 0:55:22Until the 1970s, the salinity had been almost constant,
0:55:22 > 0:55:23but then it began to fall.
0:55:28 > 0:55:32After the late '70s, we began to see a freshening of the bottom water,
0:55:32 > 0:55:35so much so that we began to doubt our own results.
0:55:35 > 0:55:37We took further samples,
0:55:37 > 0:55:40we checked with other countries who were sampling the same water,
0:55:40 > 0:55:42until eventually we became convinced that
0:55:42 > 0:55:45this change was actually happening.
0:55:51 > 0:55:55Fresh water flooding down from the melting Arctic ice caps was
0:55:55 > 0:55:57threatening to disrupt the Gulf Stream's cycle.
0:56:01 > 0:56:06And scientists warned that if the Gulf Stream shuts down...
0:56:08 > 0:56:11..global weather patterns would be thrown into turmoil.
0:56:15 > 0:56:17Europe would be plunged into a bitter winter
0:56:17 > 0:56:19that could last 100 years.
0:56:23 > 0:56:27The lush forest of the Amazon would wither and die.
0:56:29 > 0:56:32The life-giving monsoon rains would fail,
0:56:32 > 0:56:34leaving hundreds of millions of people
0:56:34 > 0:56:36to face drought and starvation.
0:56:42 > 0:56:45It could be the end of the world as we know it.
0:56:50 > 0:56:52Right now, many scientists regard climate change
0:56:52 > 0:56:57as the single greatest threat to our survival.
0:56:57 > 0:56:59It's not as dramatic as a supervolcano
0:56:59 > 0:57:01or as immediate as a killer virus,
0:57:01 > 0:57:05but the consequences of climate change could be just as apocalyptic.
0:57:07 > 0:57:09Life on Earth has been wiped out in the past,
0:57:09 > 0:57:11so we know it could happen again.
0:57:14 > 0:57:17All we can do is hope that, this time, we'll have enough warning.
0:57:21 > 0:57:26Over the last 50 years, science has done everything it can to try
0:57:26 > 0:57:29and keep one step ahead of Armageddon -
0:57:29 > 0:57:33to predict, to prevent or simply to dispel every likely threat.
0:57:33 > 0:57:35But the facts still remain.
0:57:35 > 0:57:40However advanced our science, however hard we try and prophesise,
0:57:40 > 0:57:43we can never be sure what might be lurking around the corner.
0:57:48 > 0:57:52# It's the end of the world as we know it
0:57:52 > 0:57:56# It's the end of the world as we know it
0:57:56 > 0:57:59# And I feel fine
0:58:02 > 0:58:05# It's the end of the world as we know it
0:58:06 > 0:58:11# It's the end of the world as we know it
0:58:11 > 0:58:15# It's the end of the world as we know it
0:58:15 > 0:58:17# I feel fine... #
0:58:18 > 0:58:20Subtitles by Red Bee Media Ltd
0:58:20 > 0:58:22E-mail subtitling@bbc.co.uk